Military, commercial avionics, and industrial networking equipment manufacturers are adopting fiber optic components for communication applications. An exemplary communication application is to create an operative communication link between a control system and a sensor or other data collection device. The use of fiber optic links are often used to replace existing electrical (e.g., “copper”) wiring architectures. Fiber optic links provide higher speed, improved electro-magnetic interference (EMI) performance, lower weight, and increased density. Other advantages of fiber optic links include higher data capacity using multiple light propagation modes. In addition, the fiber optic cable itself is protocol agnostic. Therefore, system upgrades often may be made without replacing the fiber optic cable.
Most fiber optic products are designed for the telecommunications market. But these products are generally not rugged enough to withstand the environmental factors that would adversely affect fiber optic systems in harsh operating environments where extreme states of vibration, shock, and temperature may be present.
One common connector (also referred to as terminus) that is used to establish a rugged connection with a mating receptacle is a terminus that is compliant with the ARINC 801 standard in the Size 16 form factor (also referred to herein as an ARINC 801 terminus or, in the plural form, ARINC 801 termini). ARINC 801 termini have been adopted in a variety of military and aerospace applications. ARINC 801 termini, however, lack components to provide cable strain relief directly on the termini and must be supported within the connector into which they are inserted. Also, removal of an ARINC 801 terminus from a mating receptacle requires a separate tool. The tool must be provided by a person servicing the optical system since the tool is not part of the optical system itself. Therefore, the tool is not always readily available or configured to fit within the space in which the terminus and receptacle are located. These shortcomings have limited the adoption and usefulness of ARINC 801 termini.
For reference, FIG. 1 illustrates a longitudinal cross-section of a conventional ARINC 801 terminus 10 connected to the terminal end of a fiber optic cable 12. The assembly of the fiber optic cable 12 and the ARINC 801 terminus 10 may be referred to as an ARINC 801 terminated fiber cable.
The fiber optic cable 12 includes a fiber optic filament 14 that is surrounded by one or more coating layers 16. The fiber optic filament 14 typically includes a core and a cladding. In the illustrated embodiment, the coating layers 16 are surrounded by strength members 18, such as KEVLAR fibers. One or more jacketing layers, also referred to as a jacket 20 surround the strength members 18.
The terminus 10 includes a tubular body 22, a ferrule 24 and a crimp sleeve 26. The jacket 20 and strength members 18 are captured between the crimp sleeve 26 and a land portion 28 at a rearward end of the body 22. The terms rearward and forward, as used herein, respectively refer to directions along the longitudinal axis of the fiber optic cable 12 away from an optical component with which an end 30 of the fiber optic filament 14 interfaces and toward the optical component.
The coating layers 16 are partially stripped from the fiber optic filament 14 and the ferrule 24 is secured to the filament 14 and/or coating layers 16, as is typical for fiber optic connectors. The ferrule 24 and forward end 30 of the filament 14 are urged in a forward direction relative to the body 22 under the force of a spring 32. An internal shoulder 34 in the body 22 provides a surface against which the rearward end of the spring 32 acts.
Compression of the crimp sleeve 26 against the jacket 20, strength members 18 and rearward portion of the body 22 limit longitudinal movement of the body 22 relative to the fiber optic cable 12.
In an exemplary use application, the terminus 10 is inserted into and retained by a receptacle 38 to establish an operative optical coupling between the filament 14 and an optical component (not shown in FIG. 1) that is located in the receptacle. Retaining of the terminus 10 may be accomplished by engagement of ends of deflectable fingers 40 against an external shoulder 36 of the body 22. Release of the terminus 10 from the receptacle is accomplished by placing a “C” shaped sleeve of a removal tool (not shown) around the fiber optic cable 12 and advancing the sleeve in a forward direction under the ends of the deflectable fingers 40 to move the fingers outward in a radial direction a sufficient distance so that the fingers no longer trap the body 22 in the receptacle. As indicated, however, such a tool is not always readily available or configured to fit within the space in which the terminus and receptacle are located. Moreover, such a tool is difficult to use in a proper manner to avoid damage to the fiber optic cable or terminus.
In a typical arrangement, the terminus 10 and the receptacle 38 are keyed. As such, proper insertion of the terminus 10 into the receptacle includes angular alignment of the respective keying features. A keying feature of the terminus 10 may include a radial projection and the keying feature of the receptacle 38 may be a coordinating slot in a housing 42 of the receptacle 38 that forms a longitudinal passage 44 for receiving the terminus 10.